<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>文件上传</title>
</head>
<body>
<h3>文件上传</h3>

<form action="/upload/file" enctype="multipart/form-data" method="post" id="image">
    <input name="dir" value="bus">
    <input type="file" name="file" multiple onchange="upload()">
</form>
<script>
     function upload  (){
         document.getElementById("image").submit();
    }
</script>
</body>
</html>